Mont-Saint-Aignan, France
Mont-Saint-Aignan, France

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Caillot G.,CNRS Institute of Organic and Analytical Chemistry | Dufour J.,CNRS Institute of Organic and Analytical Chemistry | Belhomme M.-C.,Normandie University | Poisson T.,Normandie University | And 3 more authors.
Chemical Communications | Year: 2014

Copper-catalyzed olefinic difluoroacetylation of enamides via direct C-H bond functionalization using BrCF2CO2Et is reported for the first time. It constitutes an efficient radical-free method for the regioselective synthesis of β-difluoroester substituted enamides which exhibits broad substrate scope, and thus demonstrates its potent application in a late stage fluorination strategy. This journal is © the Partner Organisations 2014.

Guillou N.,Laboratoire Of Genie Cotier Et Environnement Lgce | Thiebot J.,Normandie University
Energy | Year: 2016

Numerical assessments of environmental disturbances induced by a tidal farm project rely usually on local modifications of the friction coefficient over the area covered by a proposed array. Nevertheless, no study has investigated the sensitivity of predictions to surrounding seabed friction. The present investigation focuses on impacts of roughness parameterisation of rock outcrops, a typical seabed of tidal stream sites. A high-resolution depth-averaged circulation model is implemented in the Fromveur Strait off western Brittany, a region with strong potential for array development, integrating the heterogeneity of sediment bottom types. Rock roughness strongly influences initial predictions of tidal current and kinetic energy in the Strait with variations of available power up to 30 %. Tidal energy extraction induces noticeable reductions of tidal currents and bottom shear stresses up to 15 km from the array considered till surrounding sandbanks. Rock roughness impacts farm-induced modifications of tidal currents, bottom shear stresses and stream powers till north-eastern and southward edges of the Strait with major absolute differences identified in its central part. Surrounding sandbanks are finally suggested to variations of shear stresses from 9 to 17 % over the Bank of the Four with possible implications on local sediment deposition. © 2016 Elsevier Ltd

Gaillard S.,Normandie University | Gaillard S.,Laboratoire Of Chimie Moleculaire Et Thioorganique | Gaillard S.,CNRS Laboratory of Molecular and Thio-Organic Chemistry | Renaud J.-L.,Normandie University | And 2 more authors.
Dalton Transactions | Year: 2013

Since the discovery of the first air stable NHC, this class of compounds has been intensively studied and applied in organometallic chemistry and homogeneous catalysis due to the stability brought to the metal centre. Alternatively, phosphorus based family ligands have already a very long history in these fields of chemistry. It was naturally obvious that the NHC and the phosphorus ligands had to be mixed for the best of organometallic chemistry and homogeneous catalysis. This perspective will highlight the new synthetic routes for NHC bearing a phosphorus moiety such as NHC-phosphenium salt, N-phosphorylated-imidazolium salt, 4-phosphino or 4,5-diphosphino-imidazolium salt and tethered phosphino-imidazolium salt. Then, the recent applications in organometallic chemistry and homogeneous catalysis will be presented. © 2013 The Royal Society of Chemistry.

Achelle S.,CNRS Chemistry Institute of Rennes | Baudequin C.,Normandie University | Ple N.,Normandie University
Dyes and Pigments | Year: 2013

Though the past few decades, the development of new luminescent materials has received a lot of attention due to their applications as fluorescent sensors, in biological microscopy and in optoelectronic devices. Most of these applications are relied on intramolecular charge transfer (ICT). Presence of electron withdrawing N-heterocycles such as pyrazine and quinoxaline rings appeared therefore particularly interesting to be used as electron-attracting part in π-conjugated structures. Moreover, presence of nitrogen atoms with lone electron pairs allows to the pyrazine and the quinoxaline ring to act as effective and stable complexing agent or as base that can be protonated. This review reports luminescent small molecules and oligomers including a pyrazine or quinoxaline ring in their scaffold highlighting their applications related to photoluminescence and electroluminescence. © 2013 Elsevier Ltd. All rights reserved.

Oudeyer S.,Normandie University | Briere J.-F.,Normandie University | Levacher V.,Normandie University
European Journal of Organic Chemistry | Year: 2014

Enantioselective protonation represents an appealing approach for the construction of nonracemic chiral tertiary carbon centres, frequently found in a large range of bio-relevant organic compounds. The development of efficient catalytic processes has hitherto been regarded as a challenging goal for the synthetic chemist. Significant developments in catalytic enantioselective protonation (EP) that have been emerging over the last few years (2009-2013) are presented in this microreview. These include not only catalytic EP processes from preformed enol derivatives and useful tandem Michael addition/protonation sequences, but also unprecedented catalytic cascade reactions involving enantioselective protonation as a crucial stereo-determining step. Here, special attention is paid to the scope and limitations of these new catalytic EP processes, while valuable mechanistic insights into the catalytic cycles and into the key enantioselective protonation steps are provided. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tognetti V.,Normandie University | Joubert L.,Normandie University
Chemical Physics Letters | Year: 2013

In this letter, we assess to what extent Bader's atomic charges are appropriate to quantify charge transfers in photon absorption processes. We actually underline the fundamental role of the atomic dipole moment, which is indeed involved in the change of the electron density polarization upon excitation. This contribution cannot be neglected and enables to reproduce the total transition dipole moments with full accuracy if an enough tight integration quadrature is used. As this scheme allows separating intra-atomic density reorganization and interatomic charge transfer, it is well suited to describe through-space charge-transfer excitations. © 2012 Elsevier B.V. All rights reserved.

Guinamard R.,Normandie University | Simard C.,Normandie University | Del Negro C.,College of William and Mary
Pharmacology and Therapeutics | Year: 2013

Flufenamic acid has been known since the 1960s to have anti-inflammatory properties attributable to the reduction of prostaglandin synthesis. Thirty years later, flufenamic acid appeared to be an ion channel modulator. Thus, while its use in medicine diminished, its use in ionic channel research expanded. Flufenamic acid commonly not only affects non-selective cation channels and chloride channels, but also modulates potassium, calcium and sodium channels with effective concentrations ranging from 10-6 M in TRPM4 channel inhibition to 10-3 M in two-pore outwardly rectifying potassium channel activation. Because flufenamic acid effects develop and reverse rapidly, it is a convenient and widely used tool. However, given the broad spectrum of its targets, experimental results have to be interpreted cautiously. Here we provide an overview of ion channels targeted by flufenamic acid to aid in interpreting its effects at the molecular, cellular, and system levels. If it is used with good practices, flufenamic acid remains a useful tool for ion channel research. Understanding the targets of FFA may help reevaluate its physiological impacts and revive interest in its therapeutic potential. © 2013 Elsevier Inc.

Tite T.,Normandie University | Sabbah M.,Normandie University | Levacher V.,Normandie University | Briere J.-F.,Normandie University
Chemical Communications | Year: 2013

An asymmetric organocatalysed decarboxylative protonation reaction allowed a straightforward synthesis of α-substituted isoxazolidin-5-ones from readily available 5-substituted Meldrum's acids. This process is initiated by an anionic formal (3+2) cycloaddition-fragmentation, generated in-situ from a sulfone-amide precursor which also served as a latent source of proton. © 2013 The Royal Society of Chemistry.

Postikova S.,Normandie University | Tite T.,Normandie University | Levacher V.,Normandie University | Briere J.-F.,Normandie University
Advanced Synthesis and Catalysis | Year: 2013

Meldrum's acid has turned out to be a useful ketene equivalent when faced to nitrone dipoles to form various isoxazolidin-5-one derivatives under very mild Brønsted base organocatalytic conditions. The first asymmetric version of this original domino anionic formal [3+2] cycloaddition- decarboxylation reaction was demonstrated by means of quinine-based organocatalysts. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Jozet-Alves C.,Normandie University | Bertin M.,Normandie University | Clayton N.S.,University of Cambridge
Current Biology | Year: 2013

The recollection of past experiences allows us to recall what happened during a particular event, and where and when it occurred [1]. Since the first study on episodic-like memory in scrub-jays [2], there has been widespread acceptance of the idea that tests in animals should integrate the 'what', 'where' and 'when' components of a unique event that occurred in the past [3,4]. This is referred to as episodic-like memory rather than episodic memory per se, in acknowledgement of the lack of evidence for, or against, the phenomenological aspects that accompany episodic recollection in humans. So far, evidence for episodic-like memory has only been found in some birds and mammals. We show here that cuttlefish, cephalopod mollusks, keep track of what they have eaten, and where and how long ago they ate, in order to match their foraging behavior with the time of replenishing of different foods. Foraging in cuttlefish fulfils the criteria of 'what', 'where' and 'when' of unique events and thus provides behavioral evidence of episodic-like memory in an invertebrate. © 2013 Elsevier Ltd.

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